Embodiments of the present invention relate to high-bypass gas turbine engines, and more particularly to thrust reverser systems utilized in high-bypass turbofan engines to provide thrust reversal by diverting air from a fan bypass duct.
FIG. 1 schematically represents a high-bypass turbofan engine 10 of a type known in the art. The engine 10 is schematically represented as including a nacelle 12 and a core engine (module) 14. A fan assembly 16 located in front of the core engine 14 includes a spinner nose 20 projecting forwardly from an array of fan blades 18. The core engine 14 is schematically represented as including a high-pressure compressor 22, a combustor 24, a high-pressure turbine 26 and a low-pressure turbine 28. A large portion of the air that enters the fan assembly 16 is bypassed to the rear of the engine 10 to generate additional engine thrust. The bypassed air passes through an annular-shaped bypass duct 30 between the nacelle 12 and an inner core cowl 36 that surrounds the core engine 14, and exits the duct 30 through a fan exit nozzle 32. The nacelle 12 defines the radially outward boundary of the bypass duct 30, and the core cowl 36 defines the radially inward boundary of the bypass duct 30 as well as provides an aft core cowl transition surface to a primary exhaust nozzle 38 that extends aftward from the core engine 14.
The nacelle 12 is typically composed of three primary elements that define the external boundaries of the nacelle 12: an inlet assembly 12A, a fan cowl 12B interfacing with an engine fan case that surrounds the fan blades 18, and a thrust reverser system 12C located aft of the fan cowl 12B. The thrust reverser system 12C comprises three primary components: a translating cowl (transcowl) 34A mounted to the nacelle 12, a cascade 34B mounted within the nacelle 12, and blocker doors 34C. The lower and upper halves of FIG. 1 represent the thrust reverser system 12C stowed and deployed, respectively. The cascade 34B is typically a fixed or translating structure of the nacelle 12, whereas the transcowl 34A can be seen in the upper half of FIG. 1 as having been translated aft to expose the cascade 34B and deploy the blocker doors 34C into the duct 30 using a link arm 34D. Translation of the transcowl 34A can be provided with a slider track (not shown) oriented roughly parallel to the axis of the engine 10. The blocker doors 34C are adapted to be pivotally deployed from their stowed position radially inward from the cascade 34B (lower half of FIG. 1) to their deployed position (upper half of FIG. 1), creating a circumferential opening between the fan cowl 12B and transcowl 34A that exposes the cascade 34B and causes bypassed air flowing through the duct 30 to be diverted through the exposed cascade 34B and provide a thrust reversal effect. While two blocker doors 34C are shown in FIG. 1, a plurality of blocker doors 34C are typically circumferentially spaced around the circumference of the nacelle 12.
In addition to being capable of translating aft to deploy a thrust reverser system, transcowls of the type represented in FIG. 1 are often configured to pivot radially outward from the engine to permit maintenance access to, for example, the core engine. A nonlimiting example of such a configuration is depicted in FIG. 2, which schematically represents a cross-section of a portion of the transcowl 34A taken perpendicular to the axis of the engine 10. The transcowl 34A is equipped with two or more hinges 40 (of which one is visible in FIG. 2) that are pivotably coupled to an edge of a hinge beam 42. The opposite edge of the hinge beam 42 is slidably connected to a slider track 44, which is represented in FIG. 2 as being fixed to or otherwise interconnected with an engine pylon 13, which itself can be considered a fixed structure of the nacelle 12. The hinge beam 42 enables the transcowl 34A to translate along the slider track 44 (into the plane of FIG. 2) between stowed and deployed (aft) positions of the transcowl 34A. The hinges 40 are aligned on an axis roughly parallel to the slider track 44, and pivotably connect the transcowl 34A to the hinge beam 42 to enable the transcowl 34A to rotate from its stowed position to an open position that permits maintenance access. While such an arrangement serves its intended purpose, thrust reverser systems that are capable of reducing weight, distributing load in and improved manner, and promoting compactness are desirable.